Pooled human serum: A new culture supplement for bioreactor-based cell therapies. Preliminary results

Background aims: Bone marrow mesenchymal stromal cells (MSCs) are an appealing source for several cell-based therapies. Many bioreactors, such as the Quantum Cell Expansion System, have been developed to generate a large number of MSCs under Good Manufacturing Practice conditions by using human platelet lysate (HPL). Previously, we isolated a novel cell population in human bone marrow, mesodermal progenitor cells (MPCs), which we identified as precursors of MSCs. MPCs may represent an important cell source for regenerative medicine applications. Because HPL gives rise to a homogeneus MSC population, limiting the harvesting of other cell types, we investigated the efficacy of pooled human AB serum (ABS) to provide clinically relevant numbers of both MSCs and MPCs for regenerative medicine applications by using the Quantum System. Methods: Bone marrow aspirates were obtained from healthy adults undergoing routine total hip replacement surgery. The aspirates were used to generate primary cultures in the bioreactor. HPL and ABS were tested as supplements to culture medium. Morphological observations, cytofluorimetric analysis and lactate and glucose level assessments were performed. Results: ABS gave rise to both heterogeneous MSC and MPC populations. About 95% of cells cultured in HPL showed a fibroblast-like morphology and typical mesenchymal surface markers, but MPCs were scarcely represented. Discussion: The use of ABS appeared to sustain large-scale MSC production, as well as promote the recovery of a subset of MPCs, resulting in a suitable alternative to HPL in the cell generation based on the Quantum System.